Welding bike frames, how to get started?

[Papa]

I was told that using propane/oxy in an oxy/acetylene torch will work (much cheaper), but the air-fuel mix holes are the wrong size, and carbon monoxide may be produced, so don't use Propane/oxy in an oxy/acetylene torch.

Among most of the major torches including Harris, Victor, Smith, Uniweld and a few others, you can safely use alternate fuels in an acetylene torch without concern - and most of the brands mentioned typically offer alt fuel mixers, nozzles and tips. Acetylene tips will work with propane, but you'll need to bump-up a size or two larger to achieve the same results as O/A. However, using propane w/acetylene tips results in a more sensitive and difficult to adjust flame, which has an annoying habit of crawling away from the tip during use. It works, but not ideally. The hose should be "T" rated instead of acetylene's "R" rated hose.

My last 20 lb. (5 gallon) propane refill lasted through 15 frame builds and an assortment of other tasks. At $1.75 per gallon (or about $0.43 per 16 oz.), it's substantially cheaper than MAPP at $7 per 16 oz bottle.

 

[johnrobholmes]

I picked up a Diversion 165 yesterday, and it is just what I needed. I have been welding for about 10 years on and off, learned on stick and gas. I also have had a little 110v 135a miller Mig for a year or two. I didn't really like the mig for my use, I tend to weld really thin stuff and it is really hard to control the puddle as compared to gas. I don't really like that the wire carries the heat, because when a bead is restarted you always get a little pile of material. For spooling on a ton of filler on long welds it is great though.


Braced up my mini bike brakes today, welded up my mower to make it a mulcher, fabbed up a welding cart, and fooled around for practice. I wish it went a bit lower on the amperage, but it will be PERFECT for .035 chromoly tubing. So many projects that I couldn't do with the Mig, I can now complete. It didn't take long to get used to the Tig. The fine control is awesome.

 

[TPA]

hey john,
questions about that miller

1. did it come with the foot pedal?
2. how much trouble and expense for the argon bottle?

thanks

 

[johnrobholmes]

It has a plug for the foot pedal, but comes with a wheel on the handle for amp control

I had to sign a form for the gas, I got a 3ft bottle (40lb?) that was $200 for deposit and $40 to fill. It is 40 hours worth of welding he said. Plenty to get some projects done and not drive around too much filling bottles.

 

[Papa]

I got a 3ft bottle (40lb?) that was $200 for deposit and $40 to fill. It is 40 hours worth of welding he said. Plenty to get some projects done and not drive around too much filling bottles.

Ouch!... $40 to fill? You can experiment with lower flow rates. I run slightly below 15 CFH. And either weld inside, shield the immediate area, or simply don't weld when there's even the slightest breeze.

 

[mclovin]

I'm not sure if you are interested in attending a training class but there is a great school in Ashland, OR that is dedicated to all things bicycle..including welding frames. They also have a tech forum with welding topics on their website. Here's the link:

http://www.bikeschool.com/

 

[mud2005]

good stuff,

I've about 40 years with O/A (oxy-acetylene) before switching over to O/P (oxy/propane) about 7 years ago. I carry certs in TIG, MIG, stick and O/A, but prefer gas - especially for thin wall tubing.

whats the advantage of O/P over O/A?

my torch is a Harris and I have the "T" rated hose so O/P would be no problem.

I have heard of the bike school in Ashland, would love to attend, but $, distance and time are all factors there.

I wish I would have learned how to weld in high school. I didn't learn anything in high school.

seriously, I didn't learn a damn thing in high school either

 

[Papa]

whats the advantage of O/P over O/A?

1. It's substantially cheaper. While I haven't filled my acetylene bottle in years and performed a task-by-task comparison, my refill outlay is about 1/4 that of acetylene.

2. I no longer have the liability concerns I once had by having acetylene bottles on private property in a residential area. (check state and local codes in your area).

3. I can get refills at any RV park and a number of service stations in my area (even on weekends).

4. No bottle leases. And when the 'hydro' test date expires, I can buy a new bottle for about $30 at my local hardware store.

However... there is also disadvantages in burning propane too.

1. You'll use more oxygen. Propane has a higher stoichiometric oxygen requirement than acetylene. For the maximum flame temperature in oxygen, the ratio of the volume of oxygen to fuel gas are about 1.2 to 1 for acetylene and 4.3 to 1 for propane. Bare-in-mind, however, that the overwhelming majority of salvage yards use O/P for cutting scrap - no doubt because of expense involve considering their volume of usage. This is also one of the reasons why I use an oxygen concentrator.

2. Because of #1, oxidation is more difficult to avoid. Not a problem when brazing because that's the purpose for using flux. It is when welding that the difficulty arises. It's not impossible to weld, just requires careful attention to mixtures, line pressure adjustments and time to get acclimated.

my torch is a Harris and I have the "T" rated hose so O/P would be no problem.

Then you should already be aware of this: http://www.harrisproductsgroup.com/equipment/altcutting.asp

I wish I would have learned how to weld in high school. I didn't learn anything in high school.

No matter. If you have community college nearby that offers non-credited 'night' classes, then give the welding instructor a call. Many of the instructors of non-credited welding courses will allow the student to specify what equipment they wish to learn. So, if you wish to spend your entire (3 or 4 month) course solely on O/A, then i'm reasonably sure the instructor will approve. But call to be sure.

 

[Bullfrog]

Yes I know this is an ancient thread...hopefully some still check it.

I have a couple steel framed bikes from Walmart and plan to build a Tall Bike...and if I like it I'll add my 12T MAC motor.

Only tools I have access to at this point are a right angle grinder and an AC Craftsman stick welder that was made in the 1950s. 70A is the lowest setting available. 30 years ago I could weld Stick/MIG/TIG pretty good but it has been a looong time ago.

Going to try welding on some scrap bike frame pieces first...starting with a 6013 5/64" rod with the cracker box set on the lowest amperage of 70A. Plan is to almost tack everything together and then tie the tacks together...intermittent welding with time to for everything to cool so hopefully I won't blow holes in the tubing.

I'll try to come back here and post the results once I give a it try so the info is available for the next numbskull like me that tries to weld a bike frame with an AC stick welder AND too much amperage :lol: .

Does anybody have a better suggestion for a rod or rod diameter...remember 70A is as low as I can go ?

 

[markz]

Hard if not very hard to weld aluminum with an AC welder. You can however convert that AC welder to DC, whether it be a frequency generator which is more money to spend, or a diode rectifier which can be done for $100 if your lucky, but more like $150-$250.

I dont know if tempering the frame once its welded is a "thing" or not. Information is out there in internet land.

What I'd do is weld up the frame, then reinforce the frame with more material. You dont want to be riding and question the strength of the frame, or have any doubt whatsoever.

Lots of people out of work, so you could find a professional with a tig welder that would do the work. A year ago I messaged one who said it would cost $50. I have no clue if he was a pro or a home hobbyist. You could probably have a clue as to the kind of machine they were using. Like if they were using a small shoebox welder, vs a new large machine, eyeball the place where they are welding. See if there is a 1 ton truck with a portable welder on the back.

 

[Bullfrog]

Thanks Markz .

I am going to have some scrap pieces I can play with so I'll experiment on them. Been doing a little research and a 6013 rod is the best choice...just challenging to weld anything that is really thin with a stick welder and especially one that won't go below 70A :lol: . Going to need to keep a short arc and move fast...probably just repeated short beads IF it works at all.

Got a good friend with a TIG I can use if needed. I can weld it with the TIG...just haven't ever used it and need the friend to set it up i.e. flip the right switches and turn the right knobs. He has it wired to a high frequency power supply and some unique things have to happen to get everything working correctly. Trying to socially isolate at this point..."Covid-19" for anybody reading this a couple years from now :lol:.

 

[markz]

The process to start in welding is arc stick welding, the learning curve is easier, plus the transferable skillset from arc to MIG or TIG makes that process of welding easier to learn.

MIG and TIG is the worst to start off learning how to weld. With MIG there are so many variables, speed of line, diameter of line, gas, tips, shields, voltages, amps, flux, mig line type plus a lot of other variables, I am not a welder but a 1st time arc welder that has studied a ton youtube videos. TIG is the same way, but in that case you need a foot pedal, the stick type, flux type, voltages, amps, frequency too probably.

All I can say is practice practice and practice, hours upon hours, costing consumables and time.

Its a great skill to have, but also unhealthy breathing in the fumes.

Watch the videos and learn.
weld.com
weldingtipsandtricks.com
weldinginstruction - the young fella is good, though he changed his channel, Chucke2009 was his last channel. He seems to have copied all his videos over to new channel.

 

[Hillhater]

If you have no luck with the stick welder, you may want to consider a CARBON ARC BRAZING TORCH used on your AC welder. The arc torch works like an OA torch but no gas is used.
Brazing or Bronze welding ( different) are the traditional methods of making steel bike frames.
The temperatures are lower on the thin tubes, so no melting or blowing holes Etc.
Google Carbon arc welding ( not cutting !) .. for tips on how to make an arc torch and the materials to braze with.

 

[Overclocker]

i built this as proof that it could be done w/ a cheap fluxcore machine (fluxcore is essentially stick welding that's wire fed, same drag technique). though if i were to do it again i'd MIG it (i'm set up w/ MIG now). MIG has a "soft" arc that's less likely to blow through. no slag to clean up and a lot less BB's to remove

stick welding thin-wall bicycle frames is going to be really tough. i still have this little box of 1/16" 6013 from harbor freight. might be the electrode you need for the thin stuff

 

[dogman dan]

Harbor freight wire feed welder will do, the cheapest ones were about a hundred bucks when I got one a few years back.

DO GET, the helmet that self darkens. I never got the hang of the head flip on the old school hat.

If I can weld bikes with it, anybody with basic skills can. Steel workers call carpenters like me wood butchers. Its true, we get used to getting away with things you could not do with metal.

But I built some nice enough bikes. Helps though, if you can find a good quality cromo mtb frame for your starting point. Then you add too much weight with thin wall, mild steel scrap, such as salvaged out of walbike frames found on the trash heap. But the result is nicer, if at least your headset and bottom bracket are cut from one piece from something better.

Really good first project, make an extracycle type attachment out of an old FS mtb from Walmart. Just as a practice piece, it gives you some idea what is critical when you build a bike frame, so it rides straight.

 

[Bullfrog]

Thanks Guys.

I used to work with a guy who after using a MIG for the first time, he proclaimed even "Ray Charles" could weld with a MIG. Just FYI for those of you who don't know who "Ray" is, he is a blind piano player/musician. Very true that once you get a MIG set up, you can tell by the sound if everything is working properly. IMO the nicest thing about a MIG is no clean up...you just push the button and weld until you run out of wire or gas.

Overclocker...that is an awesome looking machine. Sent you a PM. Figured out after doing a lot of modeling that I need a mid drive set up to chase a Land Speed record since a hub motor is not built with a high enough Kv where I can gear a mid drive to achieve maximum speed with the available voltage/amperage.

 

[speedmd]

+1 on old steel frames. Mig is easy, but not typically as strong as tig if your not getting the suitable penetration. Testing is advised. If you have a torch, just fillet braze with a pre fluxed low fuming bronze, or spend the time learning the tricks of gas welding.

Bronze will allow you to build big radiuses on thin walled stuff as long as you work close. Gas welding is used by many in the ultralight air frame arena and a bit stronger, but harder to not poke holes in thin tubing if you over cook it a bit. Also a bit more difficult to make larger fillets. If your dealing with stainless or aluminum, tig or mig would be in order.

 

[markz]

Brazing can be done, and its cheaper, but its an art form that takes skill.
Practice makes perfect.

 

[speedmd]

Brazing can be done, and its cheaper, but its an art form that takes skill.
Practice makes perfect.

It is easy once you learn the tricks. Neutral flame always, use a closer flame -lower heat to build fillet, add flame distance to flatten or reduce fillet. You also always aim the flame toward the heavier components in the joint to get even fillets. A bike stand that you can rotate-position the frame joints makes it easier also.

 

[markz]

It is easy once you learn the tricks. Neutral flame always, use a closer flame -lower heat to build fillet, add flame distance to flatten or reduce fillet. You also always aim the flame toward the heavier components in the joint to get even fillets. A bike stand that you can rotate-position the frame joints makes it easier also.

Yeah, everything is easier once you learn the tricks.

 

[amberwolf]

DO GET, the helmet that self darkens. I never got the hang of the head flip on the old school hat.

If you do, DON'T get the cheap (like Harbor Freight, etc) autodarkening helmets!

They don't turn on fast enough, and they sometiems don't turn on *at all*, so you get "flashed" with the full weld arc, and you can't blink fast enough to stop it from at least temporarily blinding you...and if it happens long enough, or often enough, it could cause permanent damage.

I have been "flashed" because of them numerous times; and I am pretty sure some of my present vision problems are because of that, and not just my age.

Either get a solid-filter unit that you have to flip down, *with a dark enough filter!!!!*, or get a *good* auto-darkening helmet (which won't be cheap, but it should be safer and more reliable--it's your eyes, though).

I replaced the autodarkening part with a regular filter piece from Lowe's. Then I added a dark towel as a "curtain" across the back of the helmet, to block out all the light from behind me, so the only light I get comes thru the filter.

Then I setup very bright (like 1000w halogen floodlight equivalent) lights to shine on the weld project, so that even with the helmet down I can see what I'm doing (barely, but i can). The next project is to put an LED light that's bright enough for this directly on the handle of the welding gun, slightly aimable, that turns on with a new button on the trigger, just before it would engage the wirefeed and current.

 

[Overclocker]

this is what i used to fluxcore that frame. not exactly the cheapest model as it's MIG-capable (has gas inlet and outputs DC). i probably wouldn't recommend the harbor freight model that does AC-only and only has 2 heat settings (high and low) to weld up the critical joints on any kind of vehicle

speaking of harbor freight that auto-darkening in the pic is from HF. that particular model works well enough

speedmd is right MIG is relatively easy to use but the difficulty is in getting the settings RIGHT to get good penetration. as i mentioned earlier MIG has a soft arc that doesn't dig deep. in fact on the same machine you'll get more penetration w/ fluxcore than w/ MIG. so before doing any critical welds like on the headtube do bend tests on identical pieces of metal

 

[Bullfrog]

Wow....and I was afraid nobody would still me monitoring this old thread when I first posted :lol: .

Again...Thanks EVERYONE. There is a lot of good info in the posts above for anyone .

40 years ago, I could weld steel pretty good with a stick, MIG, and TIG...never could weld aluminum i.e. not enough practice I guess. Only problem is I haven't done any welding in 40 years .

Only equipment I currently own is the 1950s era AC only, stick welder...like I said the lowest setting is 70A which is a little too much for thin stuff. Got a pack of 6013 1/16" rods I am going to try but the max recommended amperage for a 1/16" rod is 45A. Like I said above....going to try and stitch things together and jump around with a bunch of tack welds until they connect to keep things as cool as possible. Of course it will look like crap and I do plan to try it on some scrap with the same thickness before trying it on the actual frame pieces I need to connect.

Got a feeling I'll be using my friends TIG which is the optimum solution or I'll be buying a flux core rig like Overclocker posted.

Amberwolf...IMO you hit the nail on the head. Some of the HF helmets may work but not worth the risk IMO, your eyes can't be replaced. I learned how to weld before the auto darkening helmets were invented so I like using an old fashiened non darkening helmet. BUT an auto darkening helmet that works is sweet and allows a newbie welder to get started a lot easier.

Thanks again to everyone who posted :wink: . Just imagine an old gray headed guy riding around on a TALL bike with an electric motor (12T MAC)....just the thought cracks me up. I can see the nurse at the hospital now..."Sir, how did you manage to damage your body this way"...well let me tell you :lol: :lol: :lol: .

 

[amberwolf]

. Only problem is I haven't done any welding in 40 years .

Don't worry, it's just like building a bike...once you learn, you never really forget.

Wait...maybe that was "riding" a bike....

 

[dogman dan]

Hmm, my cheap helmet has never flashed me. I have to be careful which way I face, or just the sun makes it darken too soon. I sure fried my eyes a few times trying to learn the head flip on a regular helmet.

Definitely return one, if it does not work right. I have to admit though, I only look through one eye getting started. just an old habit from sawing wood, always closing one eye when the dust flies. So I did it without thinking for welding too. Right eye squint, since it was always closer to the sawdust flying out the saw.